Percussion-tool.



w. H. MILL ER.

PERCUSSION TOOL.

APPLICATION FILED APR.15| 1915.

1,162,636. Patented Nov. 30, 1915.

I I 6mm,

COLUMBIA PLANQGRAPH CO.,WASHINGTON. Dv c.

/ UNITED STATES PATENT OFFICE.

WILLIAM H. MILLER, (3F LINCOLN, NEBRASKA.

PERCUSSION-TOOL.

Application filed April 18, 1915.

To all whom it may concern:

Be it known that 1, WILLIAM H. MILLER, a citizen of the United States, residing at Lincoln, in the county of Lancaster and State of Nebraska, have invented certain new and useful Improvements in Percussion- Tools, of which the following is a specification.

This invention relates to tools, particu larly to percussion tools and has broadly for its object the provision of an electrically operated spring driven hammer for drilling, riveting and the like.

The essential feature of the invention is the provision of adevice of this character in which the reciprocatory member is positively retracted by a. cam action operated by a power device, and periodically protracted by spring pressure when released by said cam, the energy of the reciprocatory member being transmitted to the tool by the impact of the member against the shank of the tool.

These and further objects and advantages such as simplicity, cheapness, durability, officiency and the general improvement of the art will become apparent during the course of the following description accompanied by the illustrative drawings, in which:

Figure 1 is a longitudinal sectional view of the device in position ready to deliver a blow, and Fig. 2 is a sectional view on the line 22 of Fig. 1.

Referring more particularly to the drawings, the numeral 1 designates the casing of the device which comprises a rear housing 2 within. which is disposed a suitable electric motor (not shown) and which has formed thereon a reduced shell 3 in the wall of which is formed a tubular bearing 1. The outer end of the shell 3 is internally threa (1- ed for the engagement of the externally threaded end of a tubular member 5 which has its end 6 reduced and provided with a bore 7 of considerably less diameter than the bore 8 of the major portion of the member. The bore 7 is adapted to receive the shank 9 of a tool to be operated, inward movement of the shank being prevented by a collar 10.

The reciprocatory member is designated by the numeral 11 and comprises a cylindri cal bar disposed within the bore 8 and having at its outer end a reduced extension 12 disposed Within the bore 7. At its inner Specification of Letters Patent.

Patented Nov. 30, 1915.

Serial No. 21,788.

end, the bar is cut away as shown to provide an extension 13 upon which is secured a spindle ll carrying a roller 15. The member 11 is normally urged into a position at tie nd of the bore 8 by a coil spring 16 wlncn abuts against an annular flange 17 on the member 11 and against a ring 18 threadinto the inner end of the tubular member 5.

In order that the member 11 may be reciprocated, I provide a cam mechanism as follows: The shaft 19 of the motor (not shown) extends into the shell 3 from the housing 2 and has secured upon its end a bevel pinion 20 which meshes with a bevel 21 carried by a spindle 22 revoluble within the bearing 1in the shell 3. Formed integrally upon the gear 21 is a flange 23 which has its inner periphery formed as a cam as clearly shown in Fig. 2. When the device assembled the roller 15 is disposed within the confines of the flange 23 and is held in contact with the cam surface 24 by the spring 16.

The housing 2 is provided with a suitable handle 25 by means of which the de vice may be conveniently handled.

The operation is as follows: The desired tool is positioned by inserting its shank 9 in the bore 7. The motor is then started, whereupon the shaft 19 and pinion 20 will be rotated, rotating the gear 21 and consequently the cam 2%. As the roller 15 is in contact with the cam surface, the position of the reciprocatory or hammer member 11 is controlled by the position of the cam. As the cam is rotated in the direction of the arrow, the roller 15 will ride upon the cam surface from the dotted position in Fig. 2 against the outermost portion 26 of the cam and will cause the member 11 to be gradually retracted against the pressure of the spring 16 until the roller reaches the position shown by full lines in Fig. 2, and contacts with the innermost portion 28 of the cam. lVhen the roller is engaged by the innermost point 28 of the cam. further rotation of the cam will release the roller 15, whereupon the compressed spring 16 will pull the member 11 violently outward, causing the extension 12 to impinge forcibly against the shank of the tool and deliver a powerful blow. This position is shown by dotted lines in Figs. 1 and 2. This cycle of operations is continuous so long as the motor is running.

From the foregoing description and the drawings it will be apparent that there has thus been provided a percussion tool which may be operated with great rapidity and which will be powerful and simple in action.

Having thus described my invention what I claim is:

1. A percussion tool comprising a casing having a socket to receive the shank of a tool loosely therein, a reciprocatory member disposed in said casing in position to engage said shank, said reciprocatory member comprising a cylindrical bar having a portion of its top cut away, a coil spring normally urging said member toward said shank, a roller mounted on a spindle mounted adjacent the top of said member, a driven shar't within said casing, and a cam actuated by said driven shaft and engaging said roller, whereby said reciprocatory member is retracted against the resistance of said spring; said cam at a point in its rotation releasing said member to permit said spring to force said member against said shank.

2. A percussion tool comprising a casing having a socket to receive the shank of a tool loosely therein, a reciprocatory member disposed in said casing in position to engage said shank, said reciprocatory member comprising a cylindrical bar having a portion cut away to form an extension at its upper end and a flange adjacent its other end, a roller mounted in said extension, a spring surrounding said member and abutting against said flange and a ring in said casing and urging said member toward said shank, a power driven shaft within said casing and extending longitudinally thereof, a second shaft journaled in said casing, gear connections between said shafts, the gear on said second named shaft having its face cut away to form a cam, said roller on said reciprocatory member engaging said cam and retracting said member against the resist ance of said spring and releasing it when a certain point in said cam is reached.

In testimony whereof I hereto aliix my signature in the presence of two witnesses.

WILLIAM H. MILLER.

Witnesses O. M. POE, EMIL- H. OBnRsT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents Washington, D. C. 

